<?php

class Student{
    protected $grade = 89;
    public function getGrade(){
        return $this->grade;
    }
}

interface User{    
    function getName();
    function setName($name);
}
//只有管理员可以设置公告
interface Administrator{
    function setBulletin($_bulletin);
}

class StudentAdmin extends Student implements User,Administrator{
    private $name;
    function getName() {
        return $this->name;
    }
    function setName($_name) {
        return $this->name = $_name;
    }
    function setBulletin($_bulletin){
        
    }
}

$s = new StudentAdmin();
$s->setName("李华");
echo $s->getGrade()."<br/>";
echo $s->getName()."<br/>";
echo $s->setBulletin("公告内容");